As an example just say you want to fold proteins for science.
Folding -IF protein is found THEN coin is awarded.
Actually the idea is genius. instead of performing useless work as a proof of work we might be able to couple it to some scientific problem!
regarding the folding... you'd have to use a different protein for each block (to prevent pre-computation), and the protein should only be known once the previous block has been computed. I guess you could work something out with mapping the amino acid sequence to the blockchain hash. However, instead of testing the hash you'd need to test the computed configuration - you'd need to submit a configuration which meets a criterium for the configuration energy.
The other interesting aspect of this, is that there are a bunch of different methodologies out there to fold proteins. And they all prefer different computing architectures...